A villager at Lantau's Nim Shue Wan village faces Peng Chau island and its surroundings, where the East Lantau Metropolis project is proposed by the government in Hong Kong on Oct 4, 2018.

PHOTO: REUTERS

HONG KONG - As Hong Kong recovers from one of the strongest typhoons in decades, a controversial plan to build a vast artificial island is facing intense scrutiny from environmental groups, lawmakers and academics who say it will be vulnerable to rising sea levels and storms.

The East Lantau Metropolis plan, backed by powerhouse property developers including New World Development and Henderson Land, is the government's favoured option to address a chronic housing shortage in one of the world's most expensive property markets.

But the project, which envisions housing more than 1 million people across 1,700ha of reclaimed land, is probably the worst choice, said Lam Chiu Ying, a former director of Hong Kong's weather bureau.

"Unfathomable climate risk, destruction of 22 sq km of natural marine habitat, extremely costly - with the cost comparable to the total government reserves - and strategically vulnerable transport-wise," he said.

Local media have estimated the cost at up to HK$500 billion (S$88 billion), while environmental groups estimate the cost at HK$700 billion or more.

With a population of more than seven million, the former British colony is one of the world's densest places.

The city is largely adept at dealing with typhoons, which occur regularly in southern China, yet the authorities underestimate the impact of rising sea levels and more extreme future weather, environmentalists say.

The group has deployed a glitzy marketing campaign, including an emotive video starring local celebrity Andy Lau this month. Its message: Reclamation is the best solution considering "cost effectiveness, environmental conservation, planning and infrastructure, and the preservation of property rights".

The project could be built higher to address rising sea levels and heavy tropical storms, a foundation representative told Reuters, adding that waves during typhoons were not estimated to exceed 2m where the island would be built.

The Hong Kong government has said the development would be built to standards that accounted for climate change.

Chief Executive Carrie Lam said in her policy address on Wednesday that the government was studying the planned reclamation, with the first phase of the development to start in 2025.

Temperatures are likely to rise by 1.5 deg C between 2030 and 2052 if global warming continues at its current pace, a UN report said this week.

"The government has a head-in-the-sand approach," said Hong Kong-based environmentalist Martin Williams.

Williams pointed to Osaka's Kansai airport, which was flooded after Typhoon Jebi in September, as an example of how the island project could go badly.

Ngai Hok Yan, a senior civil engineer in Hong Kong, said that the development could be built to handle massive storms but that there would always be uncertainties in predicting the size of the waves.

Tom Yam, a member of Hong Kong's Citizens Task Force on Land Resources, said that although some reclamation should be considered, the huge cost of the East Lantau project would exhaust half of Hong Kong's fiscal reserves.

"The extremely high cost, complexity risks and environmental consequences of large-scale reclamation in the middle of the ocean make the planned reclamation a wholly different animal," he said. Such a development, he added, would benefit only property tycoons and construction companies.

The Citizens Task Force said the foundation's plans were based on an inflated estimate of population growth and demand for land.

A better alternative would be to develop more than 1,000ha Hong Kong property developers already own in the city's verdant New Territories.

"Affordability, not land shortage, is the core housing issue faced by Hong Kong people. It is shocking to see how land supply continues to be moderated by government to maintain high land premium revenues," the group said in September.